Semiconductor device with SEG film active region

ABSTRACT

A semiconductor device and a method for manufacturing the same are provided. A barrier film is formed in a device separating structure, and the device separating structure is etched at a predetermined thickness to expose a semiconductor substrate. Then, a SEG film is grown to form an active region whose area is increased. As a result, a current driving power of a transistor located at a cell region and peripheral circuit regions is improved.

CROSS-REFERENCES TO RELATED APPLICATIONS

The present application claims priority to Korean patent applicationnumber 10-2006-0048670, filed on May 30, 2005, which is incorporated byreference in its entirety.

BACKGROUND OF THE INVENTION

The present invention generally relates to a semiconductor device andits method of manufacture, and, more specifically, to a method forforming a barrier film in a device separating structure, etching thedevice separating structure at a predetermined depth to expose asemiconductor substrate, and growing a SEG film to form an active regionhaving an increased area.

FIG. 1 is a plane diagram illustrating a conventional semiconductordevice.

Referring to FIG. 1, a recess gate 20 is formed perpendicular to anactive region 10 in a semiconductor substrate having a device separatingstructure that defines the active region 10.

When a trench for defining the active region is formed over thesemiconductor substrate and then filled with an oxide film to form adevice separating structure, the area of the active region is decreaseddue to recent decrease in the size of the semiconductor device.

In the above-described method for manufacturing a semiconductor device,after the device separating structure is formed, the semiconductorsubstrate of the active region is etched at a predetermined thickness toform a recess gate region and a gate pattern. However, the area of theactive region is decreased as the design rule is decreased. As a result,the current driving power is degraded as much as the decreased area ofthe active region.

BRIEF SUMMARY OF THE INVENTION

Various embodiments of the present invention are directed at providing asemiconductor device and its method of manufacture, which includesforming a barrier film in a device separating structure, etching thedevice separating structure at a predetermined depth to expose asemiconductor substrate, and growing a SEG film to form an active regionwhose area is increased.

According to an embodiment of the present invention, a semiconductordevice comprises a first device separating structure that defines afirst active region, a second device separating structure extended tothe side surface of the first active region so as to define a secondactive region overlapped with the first device separating structure, aline-type barrier film extended along the major axis of the activeregions and formed in a device separating region between the activeregions, and a recess gate perpendicular to the active region and havinga recess formed in the active region.

According to an embodiment of the present invention, a method formanufacturing a semiconductor device comprises the steps of: forming afirst device separating structure that defines a first active regionover a semiconductor substrate; forming a trench in a predeterminedregion of the first device separating structure; forming a barrier filmfor filling the trench; etching the first device separating structure ata predetermined depth to expose the sidewall of the first active region;growing the first active region to form a SEG film between the firstactive region and the barrier film, thereby forming a second activeregion extended from the first active region to the side; and, forming asecond device separating structure between the second active region.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a plane diagram illustrating a conventional semiconductordevice.

FIG. 2 is a plane diagram illustrating a semiconductor device accordingto an embodiment of the present invention.

FIGS. 3 a through 3 i are cross-sectional diagrams illustrating a methodfor manufacturing a semiconductor device according to an embodiment ofthe present invention.

DETAILED DESCRIPTION OF THE SPECIFIC EMBODIMENT

The present invention will be described in detail with reference to theaccompanying drawings.

FIG. 2 is a plane diagram illustrating a conventional semiconductordevice.

Referring to FIG. 2, a first device separating structure that defines afirst active region and a second device separating structure extended tothe side surface of the first active region so as to define a secondactive region overlapped with the first device separating structure areformed over a semiconductor substrate.

The second active region is formed from a SEG film over the first deviceseparating structure.

A line-type barrier film 120 is extended along a major axis direction ofan active region 127 and formed in the device separating region betweenthe active regions 127.

The barrier film 120 is formed deeper than the second device separatingstructure, and obtained by filling a line-type trench formed in thedevice separating region between the active regions 127.

The trench has a line-width ranging from about 10 to about 100 nm, and adepth ranging from about 300 to about 2000 Å.

The second active region extended to the side surface of the firstactive region is formed between the first active region and the barrierfilm 120. The second active region is obtained by growing a SEG filmwith a silicon layer of the first active region as a seed layer. The SEGfilm is formed to have the same height as that of the second deviceseparating structure by a planarization process.

A recess gate 175 is formed perpendicular to the active region 127, andhas a recess in the active region 127.

FIGS. 3 a through 3 i are cross-sectional diagrams illustrating a methodfor manufacturing a semiconductor device according to an embodiment ofthe present invention, FIGS. 3 a through 3 f show cross-sectionaldiagrams according to a-a′ of FIG. 2.

Referring to FIG. 3 a, a trench for separating a device (not shown) isformed by etching a semiconductor substrate at a predeterminedthickness. An oxide film for filling the trench for separating a device(not shown) is formed to obtain a first device separating structure 105that defines a first active region 100.

Referring to FIG. 3 b, after a photoresist film (not shown) is formedover the resulting structure, an exposure and developing process isperformed with an exposure mask where a local barrier film is defined,thereby obtaining a photoresist pattern 110.

The exposure mask is extended along the major axis direction of thefirst active region 100 so that a line-type space pattern is defined inthe device separating region between the first active region 100.

Referring to FIG. 3 c, the first device separating structure 105 isetched with the photoresist pattern 110 as a mask to form a trench (notshown). Then, a barrier film 120 for filling the trench (not shown) isformed over the resulting structure.

The barrier film 120 is planarized to fill the trench (not shown).

The trench (not shown) has a line-width ranging from about 10 to about100 nm, and a depth ranging from about 300 to about 2000 Å.

The barrier film 120 is formed from a nitride film, and has a thicknessranging from about 30 to about 500 Å over the first active region 100.

Referring to FIG. 3 d, the first device separating structure 105 isetched at a predetermined thickness with the barrier film 120 and thefirst active region 100 as a mask to expose the sidewall of the firstactive region 100.

The above etching process is a wet-etching process with a HF or a BOEsolution using a etching selectivity between the oxide film, which isthe first device separating structure 105, and the nitride film, whichis the barrier film 120. The first device separating structure 105 isetched at a depth ranging from about 100 to about 1500 Å so that thebarrier film 120 remains ranging from about 33 to 75%.

Referring to FIG. 3 e, the SEG film is grown with the silicon layer ofthe first active region 100 as a seed layer so that the SEG film isextended from the first active region 100 to the side surface to form asecond active region 125 overlapped with the first device separatingstructure 105.

Since the barrier film 120 is formed at both sides of the exposed activeregion 100, the SEG film is grown into the region having the barrierfilm 120 so as to have a thickness ranging from about 100 to about 2000Å thereover.

Referring to FIG. 3 f, a second device separating structure 130 isformed between the second active regions 125.

The second device separating structure 130 is formed to have a thicknessranging from about 100 to 2000 Å. Since the second device film 130 isdeposited with the first device separating structure 105, it is formedfrom an oxide film, which is the first device separating structure 105.

(i) of FIG. 3 g shows a cross-section taken along a-a′ of FIG. 2, and(ii) of FIG. 3 g is a cross-section taken along b-b′ of FIG. 2.

Referring to FIG. 3 g, a planarization process is performed to exposethe first active region 100 or the barrier film 120.

Referring to (ii) of FIG. 3 g, the second device separating structure130 is deposited over the first device separating structure 105, andetched at a predetermined thickness in FIG. 3 d so that it is used as adevice separating structure.

Referring to FIG. 3 h, the first active region 100 and the second activeregion 125 are etched at a predetermined thickness to form a recess gateregion 140.

FIG. 3 i, (i), (ii) and (iii) show cross-sections taken along a-a′, b-b′and c-c′ of FIG. 2. A gate oxide film (not shown) is formed over thesemiconductor substrate including the recess gate region 140. Then, adeposition structure including a polysilicon layer 150, a gate metallayer 160 and a gate hard mask layer 170 is formed.

Next, the deposition structure is patterned to form a gate pattern 175.Then, a spacer 190 is formed at the sidewall of the gate pattern 175.

According to an embodiment of the present invention, a barrier film isformed in a device separating structure, and the device separatingstructure is etched at a predetermined thickness to expose asemiconductor substrate. Then, a SEG film is grown to form an activeregion whose area is increased. As a result, a current driving power ofa transistor located at a cell region and peripheral circuit regions isimproved.

The above embodiments of the present invention are illustrative and notlimitative. Various alternatives and equivalents are possible. Theinvention is not limited by the lithography steps described herein. Noris the invention limited to any specific type of semiconductor device.For example, the present invention may be implemented in a dynamicrandom access memory (DRAM) device or nonvolatile memory device. Otheradditions, subtractions, or modifications are obvious in view of thepresent disclosure and are intended to fall within the scope of theappended claims.

1. A semiconductor device comprising: a first device separatingstructure that defines a first active region; a second device separatingstructure extended to the side surface of the first active region so asto define a second active region, wherein the second device separatingstructure overlaps with the first device separating structure; aline-type barrier film extended along the major axis of the activeregions and formed in a device separating region between the activeregions; and a recess gate perpendicular to the active region and with arecess formed in the active region.
 2. The semiconductor deviceaccording to claim 1, wherein the second active region is formed from aSEG film over the first device separating structure.
 3. Thesemiconductor device according to claim 1, wherein the barrier film isformed deeper than the second device separating structure.
 4. Thesemiconductor device according to claim 1, wherein the barrier film isformed from: a line-type trench formed over a semiconductor substratebetween the uni-axis direction of the second active region; and anitride film for filling the trench.
 5. The semiconductor deviceaccording to claim 4, wherein the line-width of the trench ranges from10 to 100 nm.
 6. The semiconductor device according to claim 4, whereinthe depth of the trench ranges from 300 to 2000 Å.
 7. A method formanufacturing a semiconductor device, the method comprising the stepsof: forming a first device separating structure that defines a firstactive region over a semiconductor substrate; forming a trench in apredetermined region of the first device separating structure; forming abarrier film for filling the trench; etching the first device separatingstructure at a predetermined depth to expose the sidewall of the firstactive region; growing the first active region to form a SEG filmbetween the first active region and the barrier film, thereby forming asecond active region extended from the first active region to the side;and forming a second device separating structure between the secondactive regions.
 8. The method according to claim 7, wherein theforming-a-trench step includes: forming a photoresist film over theresulting structure; forming a photoresist pattern by an exposure anddeveloping process with an exposure mask where a local barrier filmregion; and etching the first device separating structure with thephotoresist pattern as a mask to form a trench.
 9. The method accordingto claim 8, wherein the exposure mask is extended along the major axisof the second active region so that it is defined as a line-type spacepattern formed in the device separating region between the second activeregions.
 10. The method according to claim 7, wherein the line-width ofthe trench ranges from about 10 to about 100 nm.
 11. The methodaccording to claim 7, wherein the depth of the trench ranges from about300 to about 2000 Å.
 12. The method according to claim 7, wherein theforming-a-barrier-film step includes: forming a nitride film for fillingthe trench over the resulting structure; and planarizing the nitridefilm to form a barrier film filling the trench.
 13. The method accordingto claim 12, wherein the thickness of the nitride film ranges from about30 to about 500 Å.
 14. The method according to claim 7, wherein theetching-the-first-device-separating-film step is performed with thebarrier film and the first active region as a mask.
 15. The methodaccording to claim 7, wherein the depth of the first device separatingstructure ranges from about 100 to about 1500 Å.
 16. The methodaccording to claim 7, wherein theetching-the-first-device-separating-film step is a wet-etching processwith a HF or BOE solution.
 17. The method according to claim 7, whereinthe thickness of the SEG film ranges from about 100 to about 2000 Å. 18.The method according to claim 7, wherein the second device separatingstructure is formed from an oxide film.
 19. The method according toclaim 7, wherein the thickness of the second device separating structureranges from about 100 to about 2000 Å.
 20. The method according to claim7, wherein the forming-a-second-device-separating-film step includesperforming a planarizing process to form an oxide film over theresulting structure and expose the barrier film or the first activeregion.
 21. The method according to claim 20, further comprising forminga gate structure after the planarizing process.
 22. The method accordingto claim 21, wherein the forming-a-gate-structure includes: etching thefirst and second active regions at a predetermined depth to form arecess gate region; forming a gate pattern over the recess gate region;and forming a spacer at the sidewall of the gate pattern.
 23. The methodaccording to claim 22, wherein the forming-a-gate-pattern includes:forming and patterning a polysilicon layer, a gate metal layer and agate hard mask layer.